Thermostat



Af?. tARssoN ET AL,

,Augn ll, 1925.

Filed Dec. 10, 1925 Patented ug. 11, 1925.

UNITED STATES PATENT OFFICE.

AXEL JULIUS LARSSON', 0F RUNNING-E, AND KALEB EMIL ERIKSSON, 0F SALTS-J' OBADEN, SWEDEN.

THERMOSTAT.

Application filed December 10, 1923.

T o all fw hom. t may concern Be it known that we, AXEL JULIUs LARssoNand KALEB EMIL EnrnssoN, subjects of the King of Sweden, residing atRonninge,

Sweden, and Saltsjobaden, Sweden, respectively, have invented certainnew and useful Improvements in Thermostats, of which the following is aspecification.

The present invention has for its object an improvement in thermostatsfor regulating the supply of steam or hot water or for the draining ofwater of condensation or the like, yand in which the thermostat bodyconsists of materials with different coefficients of heat expansion.According to the invention, the thermostat body consists of one or moreunits, each comprising a cross and a pair of straight strips, arrangedon opposite sides of the cross and connect- .ing opposite arm ends ofthe cross. The

cross is made of a material which has a different coefficient of heatexpansion than the material forming the strips, the cross also beingmanufactured in such a manner that one pair of opposite arm ends of thecross lie in a different plane than the other pair of opposite arm ends.

When two or more units are used, they are connected with each other insuch a manner that one strip is common to two adjacent units.

In the accompanying' drawings a constructional form of the invention isillustrated.

Fig. l is a side view of a thermostat consisting of eight units.

Fig. 2 is a top plan view of the same.

Fig. 3 is a side view of one of the straight strips, and

Fig. 4 is a plan view of the same.

Fig. 5 is a side view of the cross, and

Fig. 6 is a plan view of the same.

Referring to the drawings, the thermostat body consists of the members land 2 of metals with two different coefficients of heat expansion, forinstance invar and aluminum bronze. The members l may be of invar andare made as straight strips, while the members 2 are of cruciform shape.The dierent members are connected to each Serial No. 679,763.

other in such a manner that the ends of two opposite arms of a cross,are rmly connected by rivets 8 or the like to the ends of a strip 1arranged at one side of the cross, while the two remaining ends of thesame cross, in a similar way are connected to the ends of a second stripl, situated at the opposite side of the cross. Two opposite ends of thenext cross are then connected with the ends of one of the abovementioned strips, which thus is connected to two opposite ends on twocrosses. By this arrangement a thermostat is obtained, which at a verysmall variation of temperature undergoes considerable expansion orcontraction. Then the temperature increases, the central parts of thecrosses 2 are forced to move away from the intermediate parts of thestrips l, and thus the length of thermostat, formed of the combinedunits, is increased in a degree corresponding to the number of units.For facilitating the bending of the crosses 2 in a desired direction,each cross is arranged in such a manner that two opposite ends of thecross lie in a different plane than the other two ends.

Claims:

l. Thermostats for regulating the supply of steam, hot water or thedraining of water -of condensation or the like including a bodyconsisting of materials with different coeflicients of heat expansion,said body including a unit, consisting of a cross and a pair of singlestraight strips, said strips being arranged on opposite sides of thecross and connecting opposite arm ends ofthe cross, the cross beingformed of a material having a different 'coeflicient of heat eXpansionthan the material of which the strips are manufactured, the cross alsobeing arranged in such a manner that one pair of opposite arm ends liein a different plane from the other pair of opposite arm ends.

2. A thermostat as claimed in claim l including a plurality of saidunits, one of the strips being common to and connected to opposite armends of two adjacent units.

AXEL J ULIUS LARSSON. KALEB EMIL ERIKSSON.

